Cutaway views of (a) the breast of a woman who is not pregnant and (b) the breast of a lactating wom

Cutaway views of (a) the breast of a woman who is not pregnant and (b) the breast of a lactating woman.



During birth, the hormone oxytocin stimulates muscle contractions that force a fetus out of its mother’s body.

Prolactin promotes mammary gland enlargement and milk production. Oxytocin released in response to suckling causes secretion of milk.

Both mother and child benefit from breast-feeding. In addition to nourishing the newborn, breast-feeding protects it from infection. The mother benefits from weight loss, contraceptive effects, and decreased cancer risk.